Precisely. Religion has been around since the beginning of man. Religion has evolved as our technology and understanding of the universe has. It is more likely than not that the human unconscious created 'religion' in hopes of explaining the unexplained and creating a purpose for mankind. Someone probably came up with the idea of a/many supreme beings, and the people liked this idea. And so, over time religion has evolved from the original pagan polytheistic ideologies to modern christian monotheism.
Isn't scientific research also a hope of "explaining the unexplained"? Lots of people have come up with theories of specific dynamics that govern the universe without being able to prove their origin, and people liked this idea. And so over time, science has evolved from the original voodoo to modern scientific methodology.
Oh, and Christianity isn't the only religion. There's many more out there, and some of them are as popular as ever.